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Jason Low 1d8fe7dc80 locking/mutexes: Unlock the mutex without the wait_lock 
When running workloads that have high contention in mutexes on an 8 socket
machine, mutex spinners would often spin for a long time with no lock owner.

The main reason why this is occuring is in __mutex_unlock_common_slowpath(),
if __mutex_slowpath_needs_to_unlock(), then the owner needs to acquire the
mutex->wait_lock before releasing the mutex (setting lock->count to 1). When
the wait_lock is contended, this delays the mutex from being released.
We should be able to release the mutex without holding the wait_lock.

Signed-off-by: Jason Low <jason.low2@hp.com>
Cc: chegu_vinod@hp.com
Cc: paulmck@linux.vnet.ibm.com
Cc: Waiman.Long@hp.com
Cc: torvalds@linux-foundation.org
Cc: tglx@linutronix.de
Cc: riel@redhat.com
Cc: akpm@linux-foundation.org
Cc: davidlohr@hp.com
Cc: hpa@zytor.com
Cc: andi@firstfloor.org
Cc: aswin@hp.com
Cc: scott.norton@hp.com
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1390936396-3962-4-git-send-email-jason.low2@hp.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-03-11 12:14:54 +01:00
..
cpu
sched/preempt: Fix up missed PREEMPT_NEED_RESCHED folding
2014-01-13 17:38:55 +01:00
debug
kgdb/kdb: Fix no KDB config problem
2014-01-25 08:55:09 +01:00
events
This pull request has a new feature to ftrace, namely the trace event
2014-01-22 16:35:21 -08:00
gcov
gcov: reuse kbasename helper
2013-11-13 12:09:34 +09:00
irq
Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2013-12-02 10:15:39 -08:00
locking
locking/mutexes: Unlock the mutex without the wait_lock
2014-03-11 12:14:54 +01:00
power
Merge branch 'for-3.14/core' of git://git.kernel.dk/linux-block
2014-01-30 11:19:05 -08:00
printk
printk: flush conflicting continuation line
2014-01-23 16:36:56 -08:00
rcu
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
2014-01-28 08:38:04 -08:00
sched
Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2014-01-31 09:02:51 -08:00
time
Merge branch 'timers/core' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks into timers/urgent
2014-01-25 08:27:26 +01:00
trace
Merge branch 'for-3.14/core' of git://git.kernel.dk/linux-block
2014-01-30 11:19:05 -08:00
.gitignore
Ignore generated file kernel/x509_certificate_list
2013-12-10 18:21:34 +00:00
acct.c
fs: Fix hang with BSD accounting on frozen filesystem
2013-05-04 14:57:58 -04:00
async.c
async: rename and redefine async_func_ptr
2013-03-12 13:59:14 -07:00
audit_tree.c
fsnotify: remove pointless NULL initializers
2014-01-21 16:19:41 -08:00
audit_watch.c
fsnotify: remove pointless NULL initializers
2014-01-21 16:19:41 -08:00
audit.c
audit: fix location of __net_initdata for audit_net_ops
2014-01-17 17:14:32 -05:00
audit.h
audit: Convert int limit uses to u32
2014-01-14 14:54:00 -05:00
auditfilter.c
audit: log on errors from filter user rules
2014-01-13 22:32:31 -05:00
auditsc.c
audit: fix dangling keywords in audit_log_set_loginuid() output
2014-01-13 22:32:38 -05:00
backtracetest.c
…
bounds.c
mm: do not allocate page->ptl dynamically, if spinlock_t fits to long
2013-12-20 12:25:45 -08:00
capability.c
audit: Simplify and correct audit_log_capset
2014-01-13 22:26:48 -05:00
cgroup_freezer.c
cgroup: replace cftype->read_seq_string() with cftype->seq_show()
2013-12-05 12:28:04 -05:00
cgroup.c
Merge branch 'for-3.14' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
2014-01-21 17:51:34 -08:00
compat.c
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal
2013-05-01 07:21:43 -07:00
configs.c
proc: Supply PDE attribute setting accessor functions
2013-05-01 17:29:18 -04:00
context_tracking.c
context_tracking: Wrap static key check into more intuitive function name
2013-12-02 20:43:14 +01:00
cpu_pm.c
…
cpu.c
Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2013-11-14 16:55:11 +09:00
cpuset.c
cgroup: replace cftype->read_seq_string() with cftype->seq_show()
2013-12-05 12:28:04 -05:00
crash_dump.c
…
cred.c
…
delayacct.c
kernel/delayacct.c: remove redundant checking in __delayacct_add_tsk()
2013-11-13 12:09:12 +09:00
dma.c
…
elfcore.c
switch elf_core_write_extra_phdrs() to dump_emit()
2013-11-09 00:16:23 -05:00
exec_domain.c
…
exit.c
introduce for_each_thread() to replace the buggy while_each_thread()
2014-01-21 16:19:46 -08:00
extable.c
kernel/extable: fix address-checks for core_kernel and init areas
2013-11-28 09:49:41 -08:00
fork.c
exec: kill task_struct->did_exec
2014-01-23 16:37:02 -08:00
freezer.c
libata, freezer: avoid block device removal while system is frozen
2013-12-19 13:50:32 -05:00
futex_compat.c
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal
2013-02-23 18:50:11 -08:00
futex.c
futex: Allow architectures to skip futex_atomic_cmpxchg_inatomic() test
2014-03-03 11:32:08 +01:00
groups.c
userns: Kill nsown_capable it makes the wrong thing easy
2013-08-30 23:44:11 -07:00
hrtimer.c
sched/deadline: Add SCHED_DEADLINE structures & implementation
2014-01-13 13:41:06 +01:00
hung_task.c
hung_task: Display every hung task warning
2014-01-25 12:13:33 +01:00
irq_work.c
Merge branch 'nohz/printk-v8' into irq/core
2013-02-05 00:48:46 +01:00
itimer.c
…
jump_label.c
static_key: WARN on usage before jump_label_init was called
2013-10-19 19:45:35 -04:00
kallsyms.c
kernel: kallsyms: memory override issue, need check destination buffer length
2013-04-15 15:17:26 +09:30
kcmp.c
…
Kconfig.freezer
…
Kconfig.hz
kernel: remove CONFIG_USE_GENERIC_SMP_HELPERS
2013-11-15 09:32:22 +09:00
Kconfig.locks
locking: Fix copy/paste errors of "ARCH_INLINE_*_UNLOCK_BH"
2013-05-28 08:50:00 +02:00
Kconfig.preempt
…
kexec.c
kernel/kexec.c: use vscnprintf() instead of vsnprintf() in vmcoreinfo_append_str()
2014-01-27 21:02:40 -08:00
kmod.c
kernel/kmod.c: check for NULL in call_usermodehelper_exec()
2013-09-30 14:31:02 -07:00
kprobes.c
kprobes: use KSYM_NAME_LEN to size identifier buffers
2013-11-13 12:09:26 +09:00
ksysfs.c
kdump: fix exported size of vmcoreinfo note
2014-01-23 16:37:03 -08:00
kthread.c
kthread: make kthread_create() killable
2013-11-13 12:08:59 +09:00
latencytop.c
…
Makefile
KEYS: Remove files generated when SYSTEM_TRUSTED_KEYRING=y
2013-12-13 15:59:11 +00:00
module_signing.c
keys: change asymmetric keys to use common hash definitions
2013-10-25 17:15:18 -04:00
module-internal.h
KEYS: Separate the kernel signature checking keyring from module signing
2013-09-25 17:17:01 +01:00
module.c
module: Add missing newline in printk call.
2014-01-21 09:59:16 +10:30
notifier.c
…
nsproxy.c
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
2013-09-07 14:35:32 -07:00
padata.c
padata: Fix wrong usage of rcu_dereference()
2013-12-05 21:28:42 +08:00
panic.c
panic: Make panic_timeout configurable
2013-11-26 12:12:26 +01:00
params.c
params: improve standard definitions
2013-12-04 14:09:46 +10:30
pid_namespace.c
pid_namespace: make freeing struct pid_namespace rcu-delayed
2013-10-24 23:43:29 -04:00
pid.c
pidns: fix free_pid() to handle the first fork failure
2013-09-30 14:31:03 -07:00
posix-cpu-timers.c
posix-timers: Convert abuses of BUG_ON to WARN_ON
2013-12-09 16:56:29 +01:00
posix-timers.c
posix-timers: Remove unused variable
2013-04-18 12:51:19 +02:00
profile.c
kernel: delete __cpuinit usage from all core kernel files
2013-07-14 19:36:59 -04:00
ptrace.c
exec/ptrace: fix get_dumpable() incorrect tests
2013-11-13 12:09:33 +09:00
range.c
range: Do not add new blank slot with add_range_with_merge
2013-06-18 11:32:10 -05:00
reboot.c
kexec: migrate to reboot cpu
2013-12-18 19:04:50 -08:00
relay.c
kernel: delete __cpuinit usage from all core kernel files
2013-07-14 19:36:59 -04:00
res_counter.c
memcg: reduce function dereference
2013-09-12 15:38:02 -07:00
resource.c
kernel/resource.c: remove the unneeded assignment in function __find_resource
2013-07-03 16:08:06 -07:00
seccomp.c
seccomp: allow BPF_XOR based ALU instructions.
2013-03-26 11:07:19 +11:00
signal.c
kernel/signal.c: change do_signal_stop/do_sigaction to use while_each_thread()
2014-01-23 16:37:02 -08:00
smp.c
kernel/smp.c: remove cpumask_ipi
2014-01-30 16:56:54 -08:00
smpboot.c
kernel: delete __cpuinit usage from all core kernel files
2013-07-14 19:36:59 -04:00
smpboot.h
…
softirq.c
Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2014-01-31 09:02:51 -08:00
stacktrace.c
…
stop_machine.c
stop_machine: Fix race between stop_two_cpus() and stop_cpus()
2013-11-11 12:43:38 +01:00
sys_ni.c
unify compat fanotify_mark(2), switch to COMPAT_SYSCALL_DEFINE
2013-05-09 13:46:38 -04:00
sys.c
kernel/sys.c: k_getrusage() can use while_each_thread()
2014-01-23 16:37:02 -08:00
sysctl_binary.c
kernel/sysctl_binary.c: use scnprintf() instead of snprintf()
2013-11-13 12:09:33 +09:00
sysctl.c
Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2014-01-31 08:59:46 -08:00
system_certificates.S
KEYS: correct alignment of system_certificate_list content in assembly file
2013-12-10 18:25:28 +00:00
system_keyring.c
KEYS: correct alignment of system_certificate_list content in assembly file
2013-12-10 18:25:28 +00:00
task_work.c
task_work: documentation
2013-09-11 15:58:27 -07:00
taskstats.c
genetlink: only pass array to genl_register_family_with_ops()
2013-11-19 16:39:05 -05:00
test_kprobes.c
kernel/: rename random32() to prandom_u32()
2013-04-29 18:28:42 -07:00
time.c
sched: Rename sched.c as sched/core.c in comments and Documentation
2013-06-19 12:58:42 +02:00
timeconst.bc
kernel: Replace timeconst.pl with a bc script
2013-02-16 23:17:25 +01:00
timer.c
timer: Convert kmalloc_node(...GFP_ZERO...) to kzalloc_node(...)
2013-11-19 14:59:50 +01:00
tracepoint.c
Tracing updates for Linux 3.10
2013-04-29 13:55:38 -07:00
tsacct.c
…
uid16.c
userns: Kill nsown_capable it makes the wrong thing easy
2013-08-30 23:44:11 -07:00
up.c
kernel: provide a __smp_call_function_single stub for !CONFIG_SMP
2013-11-15 09:32:22 +09:00
user_namespace.c
KEYS: Add per-user_namespace registers for persistent per-UID kerberos caches
2013-09-24 10:35:19 +01:00
user-return-notifier.c
hlist: drop the node parameter from iterators
2013-02-27 19:10:24 -08:00
user.c
KEYS: fix uninitialized persistent_keyring_register_sem
2013-12-13 15:59:11 +00:00
utsname_sysctl.c
kernel/utsname_sysctl.c: put get/get_uts() into CONFIG_PROC_SYSCTL code block
2013-02-27 19:10:22 -08:00
utsname.c
userns: Kill nsown_capable it makes the wrong thing easy
2013-08-30 23:44:11 -07:00
watchdog.c
watchdog: update watchdog_thresh properly
2013-09-24 17:00:25 -07:00
workqueue_internal.h
sched: Rename sched.c as sched/core.c in comments and Documentation
2013-06-19 12:58:42 +02:00
workqueue.c
Merge branch 'for-3.14' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
2014-01-21 17:46:31 -08:00